The present disclosure relates generally to methods and apparatus for providing haptic feedback, and more particularly relates to methods and apparatus for localizing of haptic feedback by limiting the effects of vibratory crosstalk between feedback positions.
The term “haptic” refers to touch or tactile sensation, and the term “haptic feedback system” refers to a system configured to provide a selective tactile feedback sensation (such as a vibration or other physical sensation, etc.) at a contact location of a surface in response to contact of a user at that location. Such haptic feedback systems include an input surface and one or more actuators (such as piezoelectric transducers, electromechanical devices, and/or other vibration inducing devices) that are mechanically connected to the back of the input surface. Drive electronics coupled to the one or more actuators cause the actuators to induce a selected vibratory response into the surface to which they are attached, thereby providing a tactile sensation to a user.
Many conventional devices, such as touch screen interfaces, have multiple feedback locations provided on a single surface, where typically each contact location will correspond to a user input location. With many such touch screen devices, a single actuator vibrates the entire surface relative to input at any one of several locations on the surface. Such devices offer essentially no localization of the haptic feedback. However, devices have been proposed where multiple actuators are distributed along the surface, each at a separate contact location, to provide some localization to the user feedback. However, because there are multiple actuator inputs into a single surface, the vibration can propagate to other locations, thus limiting the ultimate localization effect.
The problem of propagating tactile sensations from the selected input location to other locations across the input surface (sometimes referred to as “vibratory crosstalk” or “tactile crosstalk”) can be especially pronounced in multi-touch systems, such as a virtual keyboard or keypad, a multi-touch track pad, or a touch screen interface, having multiple contact locations. In such systems, the number of actuators can be increased to improve the granularity of the tactile sensation; however, such systems typically still suffer from undesired vibratory crosstalk.
Accordingly, embodiments of haptic feedback systems and methods are disclosed below that provide new methods and apparatus providing improved localization of haptic feedback provided through an input surface.